The two streams meet at a confluence. It takes many tributary streams to form a river. A river grows larger as it collects water from more tributaries. Streams usually form rivers in the higher elevations of mountains and hills. The areas of depression between hills or mountains are known as valleys.
The world's fastest production single piston engine aircraft produced in Great Britain, deployed from 1945 to 1953. Heavily Modified Sea Fury aircraft can be seen today as air racers. Heinkel He-162 562 mph. Arguably the fastest WW II jet fighter.
What is the Fastest Airplane in the World? The Lockheed SR-71, the fastest airplane in the world. Though not the world's absolute fastest aircraft, the Lockheed Martin F-22 Raptor can accelerate to and sustain supersonic speeds without the use of its afterburners. The Boeing 747 has a cruise speed of 550 miles per hour, which is actually faster than the top speed combat fighters could achieve in World War Two.